Introduction

I was recently introduced to the game Ruzzle, a word finding game with some Scrabble-like scoring components. If you’re not familiar with it, check out their website and watch the quick introductory video.

Ruzzle screenshot

I was fascinated by how the game calculated all the possible words on each board. So I decided to program it. Check out the Ruzzle demo page, which creates a randomized board and finds all possible words.

Overview

The way to do this search for all possible words is by viewing the letters as a directed graph where the letters are nodes and edges are connections between adjacent letters.

Note the variable $dictionaryFirstNLetters. We use this to optimize our DFS by allowing us to “bail out” early in our search if we see that there are no words that start with our $currentResult. If you try taking out this code, you’ll see that this algorithm can take an incredibly long time to run – even with a $maxDepth of 6 characters (only find words with up to 6 characters), the runtime can easily reach a minute. It increases quickly as $maxDepth is increased.

What’s next

This crash-course in Ruzzle programming doesn’t address the scoring, graphics, or actual gameplay. But these would all be fairly easy to add to the basic chasis that we’ve created here. I’ll leave that as an exercise to the reader 🙂